18990985 has 16 divisors (see below), whose sum is σ = 25611264. Its totient is φ = 13413312.

The previous prime is 18990973. The next prime is 18990991. The reversal of 18990985 is 58909981.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 18990985 - 2¹⁵ = 18958217 is a prime.

It is a super-2 number, since 2×18990985² = 721315022540450, which contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4857 + ... + 7846.

It is an arithmetic number, because the mean of its divisors is an integer number (1600704).

Almost surely, 2^18990985 is an apocalyptic number.

It is an amenable number.

18990985 is a deficient number, since it is larger than the sum of its proper divisors (6620279).

18990985 is a wasteful number, since it uses less digits than its factorization.

18990985 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12744.

The product of its (nonzero) digits is 233280, while the sum is 49.

The square root of 18990985 is about 4357.8647294289. The cubic root of 18990985 is about 266.7979553170.

The spelling of 18990985 in words is "eighteen million, nine hundred ninety thousand, nine hundred eighty-five".